Remember that a laptop will have two adaptors, one for wired and one for wireless.
here are mine (Win7)
Wired on the left, wireless on the right.
Clicking on an adaptor opens the screen on the left:
Clicking "properties" in the left screen opens the screen on the right. In the right hand screen select the "Power Management" tab,
Remember to do this on both the wired and wireless adaptors.
Lets do this, follow the numbers:
Clicking "properties" will open the following:
Clicking on the "configure" button above will open this:
Close all over dialog boxes.